The present invention relates to improvements in a CAD/CAM device used for an electric discharge machine that conducts electric discharge machining on a workpiece by supplying electric power for machining to between an electrode and the workpiece.
FIG. 4 is an arrangement view of an electric discharge machine. In the view, reference numeral 1 is a mechanical body of the electric discharge machine, reference numeral 2 is a control section of the electric discharge machine, reference numeral 3 is a motor of Z-axis, reference numeral 4 is a head, reference numeral 5 is a clamp device, reference numeral 6 is a surface plate, reference numeral 7 is a machining tank, reference numeral 8 is an insulating machining solution stored in the machining tank 7, reference numeral 9 is a motor for driving the machining tank, reference numeral 10 is a manual switch for elevating the machining tank, reference numeral 11 is an automatic electrode replacing device, reference numeral 12 is a machining electric power supply means, reference numeral 13 is a memory for storing an NC program, reference numeral 14 is an NC program analysis section, reference numeral 15 is a shaft drive section, reference numeral 16 is a machining tank drive section, reference mark E is an electrode, reference mark W is a workpiece, and reference mark HL is a level of a surface of the machining solution.
The shaft drive section 15, the motor 3 of Z-axis and motors of X-axis and Y-axis, which are not shown in the view, correspond to a positioning means. The machining tank drive section 16 and the machining tank drive motor 9 correspond to a machining tank drive means for changing level HL of the surface of the machining solution with respect to workpiece W when the machining tank 7 is driven and made to ascend and descend.
Electrode E can be attached to and detached from the clamp device 5 of the head 4 by the automatic electrode replacing device 11. Electrode E is attached to the clamp device 5 of the head 4, and workpiece W is put and fixed onto the surface plate 6 arranged in the machining tank 7. Under the above condition, electrode E and workpiece W are relatively positioned by the positioning means, and then electric discharge is generated in the machining solution 8 while voltage is being impressed upon between electrode E and workpiece W by the machining electric power supply means 12. When electric discharge is generated between electrode E and workpiece W, workpiece W is melted and removed, so that electric discharge machining can be carried out.
An NC program for giving a command of operation of the electric discharge machine is stored in the memory 13. This NC program is analyzed by the NC program analysis section 14. This NC program analysis section 14 outputs moving commands to the shaft drive section 15 and the machining tank drive section 16.
An ascending and descending motion of the machining tank 7 is carried out by the machining tank drive motor 9 that is driven by the machining tank drive section 16. When the machining tank 7 is made to ascend and descend by the machining tank drive motor 9, level HL of the surface of the machining solution is changed with respect to the position of workpiece W. For example, as disclosed in JP-A-5-261620, level HL of the surface of the machining solution is set at a position higher than the level of workpiece W by a distance not less than 50 mm, for example, level HL of the surface of the machining solution is set at a position higher than the level of workpiece W by a safe distance of about 100 mm. The reason why level HL of the surface of the machining solution is set at the position described above will be explained as follows. When level HL of the surface of the machining solution is too low with respect to the level of workpiece W, electric discharge is conducted in air. Accordingly, there is a possibility of the occurrence of fire. When level HL of the surface of the machining solution is too high with respect to the level of workpiece W, it is difficult for an operator to observe a state of electric discharge. Further, the clamp device 5 is soaked in the machining solution 8, which could cause a mechanical breakdown.
When machining solution surface level HL is set at a level which is obtained when a safe distance is added to the level of workpiece W (This level is referred to as xe2x80x9csafe levelxe2x80x9d HLS hereinafter.), it is necessary for an operator to adjust the level of the machining tank 7 by the manual switch 10 for ascending and descending the machining tank or alternatively it is necessary for an operator to give a command of the safe level or safe distance by an NC program. Each time the level of workpiece W is changed, safe level HLS must be adjusted, and further the operator must always conduct the adjustment.
FIG. 5 is a system arrangement view of the conventional CAD/CAM device 17. In the view, reference numeral 18 is an electrode drawing data, reference numeral 19 is a workpiece drawing data, reference numeral 20 is a path deciding section, reference numeral 21 is an NC program, reference numeral 22 is a path checking means, and reference numeral 23 is a display means such as a CRT.
In the conventional CAD/CAM device 17, the electrode drawing data 18 and the workpiece drawing data 19 are read in, and the path deciding section 20 decides a path of the machining motion according to the data which have been read in and the NC program 21 is created. The thus created NC program 21 is stored in the memory 13 arranged in the control section 2 of the electric discharge machine shown in FIG. 4. The path check means 22 confirms a path between electrode E and workpiece W.
As the method of checking the NC program 21, there are provided two methods. One is a method of graphic check conducted on a display of the display means 23, and the other is a method of dry-run check conducted by a dry running. The method of graphic check is conducted as follows. In the graphic check, the machine is not actually operated but the NC program 21 is operated on the display means 23 or the display of the electric discharge machine so as to conduct checking on each shaft. The path is graphically displayed on the display means 23 or the display of the electric discharge machine, so that operation of each shaft can be checked by the coordinate values shown on the display. In the method of dry-run check, operation of each shaft is checked while the machine is being operated. Dry running in which the workpiece is not actually machined is conducted while the machining solution 8 is not being provided, so that operation of each shaft can be checked at high speed.
Setting of level HL of the machining solution at safe level HLS depends upon the operator as described above. Therefore, it is impossible for the conventional methods of graphic check and dry-run check to check a positional relation between electrode E and level HLS of the surface of the machining solution. Accordingly, even if graphic check and dry-run check are conducted, the following problems may be encountered. When electrode E to be used is too short, the clamp device 5 is soaked in the machining solution 8 in the process of electric discharge machining. Alternatively, when machining is conducted at a deep position in the machining solution, the clamp device 5 is soaked in the machining solution 8.
When it is found that electrode E cannot be used as described above because the clamp device 5 has been soaked in the machining solution 8 after the actual machining process, electrode E must be manufactured again, which causes a decrease in the productivity and an increase in the manufacturing cost.
Especially in the case where a profile of workpiece W is complicated or a plurality of workpieces W, the level of which are different from each other, are present, and further in the case where machining is conducted while a plurality of electrodes E are being replaced by the automatic electrode replacing device 11, from the viewpoint of accomplishing automation, it is very important that safe level HLS necessary for actual machining operation is recognized and the machining tank 7 is automatically driven so that level HL of the surface of the machining solution can be set at safe level HLS. Furthermore, in the case where the profile of workpiece W is complicated, it is necessary to precisely check the length of electrode E before actual machining operation is started.
The present invention has been accomplished to solve the above problems. It is an object of the present invention to provide a CAD/CAM device used for an electric discharge machine characterized in that: a safe level of an electrode can be recognized in an actual machining process and a machining tank is automatically driven so that a level of a surface of the machining solution can be set at the safe level; and even if a profile of a workpiece is complicated, it is possible to check whether or not a clamp device is soaked in the machining solution when actual machining is conducted.
The present invention provides a CAD/CAM device for an electric discharge machine comprising: a machining tank for storing a machining solution; a positioning device for relatively moving a workpiece, which is fixed to a surface plate arranged in the machining tank, and an electrode; a machining electric power supply means for supplying machining electric power to between the workpiece and the electrode; and a machining tank drive means for changing a level of a surface of the machining solution with respect to the workpiece by driving the machining tank, the CAD/CAM device for an electric discharge machine further comprising a check means for checking whether or not a level of a predetermined position of a device to be protected from being soaked in the machining solution is lower than a safe level of a surface of the machining solution when a safe level of the surface of the machining solution, which is obtained when a predetermined safe distance is added to a level of a predetermined position of the workpiece with respect to a predetermined reference position, is compared with the level of the predetermined position of the device with respect to the predetermined reference position before conducting actual machining.
The present invention provides a CAD/CAM device for an electric discharge machine comprising: a machining tank for storing a machining solution; a positioning device for relatively moving a workpiece, which is fixed to a surface plate arranged in the machining tank, and an electrode; a machining electric power supply means for supplying machining electric power to between the workpiece and the electrode; and a machining tank drive means for changing a level of a surface of the machining solution with respect to the workpiece by driving the machining tank, the CAD/CAM device for an electric discharge machine further comprising a check means for checking whether or not a level of a clamp is lower than a safe level of the machining solution when a safe level of the surface of the machining solution, which is obtained when a predetermined safe distance is added to a level of a predetermined position of the workpiece with respect to a predetermined reference position, is compared with a level of a clamp which is obtained when a length of the electrode is added to a level of a machining finishing position of the workpiece with respect to the predetermined reference position before conducting actual machining.
The present invention provides a CAD/CAM device for an electric discharge machine comprising: a machining tank for storing a machining solution; a positioning device for relatively moving a workpiece, which is fixed to a surface plate arranged in the machining tank, and an electrode; a machining electric power supply means for supplying machining electric power to between the workpiece and the electrode; and a machining tank drive means for changing a level of a surface of the machining solution with respect to the workpiece by driving the machining tank, the CAD/CAM device for an electric discharge machine further comprising a check means for checking whether or not a level of a clamp is lower than a safe level of the machining solution when a safe level of a surface of the machining solution, which is obtained when a predetermined safe distance is added to a level of a predetermined position of the workpiece with respect to a predetermined reference position on the basis of workpiece drawing data, is found and when a safe level of the surface of the machining solution is compared with a level of a clamp which is found when a length of the electrode is added to a level of a machining finishing position of the workpiece with respect to the predetermined reference position on the basis of electrode drawing data before conducting actual machining.
The present invention provides a CAD/CAM device for an electric discharge machine comprising: a machining tank for storing a machining solution; a positioning device for relatively moving a workpiece, which is fixed to a surface plate arranged in the machining tank, and an electrode; a machining electric power supply means for supplying machining electric power to between the workpiece and the electrode; and a machining tank drive means for changing a level of a surface of the machining solution with respect to the workpiece by driving the machining tank, the CAD/CAM device for an electric discharge machine further comprising a machining tank level deciding means for deciding a level of the machining tank so that a level of a surface of the machining solution can be a level obtained when a predetermined safe level is added to a level of a predetermined position of the workpiece which is found on the basis of workpiece drawing data, wherein an NC program to drive the machining tank drive means is outputted so that the level of the machining tank can be a value found by the machining tank level deciding means.
The CAD/CAM device for an electric discharge machine of the present invention is composed as described above. Therefore, it is possible for the device to recognize a safe level of a surface of a machining solution which is necessary when machining is actually conducted, and it is also possible for the device to automatically drive a machining tank so that a level of the machining solution in the machining tank can be set at the safe level. It is also possible for the device to check before machining is actually conducted whether or not a clamp device is soaked in the machining solution in the process of actual machining.